Nontyphoid Salmonella empyema in a patient with type 2 diabe
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A 56-year-old male with uncontrolled type 2 diabetes mellitus (hemoglobin A1c = 18.1%) and heavy alcohol use presented with 1 month of pleuritic chest pain, productive cough, and 10-pound weight loss. He denied any gastrointestinal (GI) symptoms. His examination demonstrated temporal wasting, decreased breath sounds in the left lower and middle lung fields, and a benign abdomen. Laboratory studies revealed a white blood cell count of 16,900/mm3 with 30% bandemia. CT abdomen was negative for intra-abdominal infection.

CT thorax demonstrated left lower lobe consolidation with an elliptical hyperdensity abutting the cephalic portion of the left oblique fissure and adjoining pleural effusion. The differential diagnosis included pleural fluid loculation, intrapulmonary abscess, and malignancy with or without secondary abscess formation. Following chest tube placement in the left basal pleural effusion, blood, sputum, and pleural fluid cultures grew Salmonella enterica serovar Enteritidis. Pleural fluid cultures also grew Streptococcus intermedius, suggesting GI-pulmonary translocation of Salmonella via aspiration.

The patient was treated with ceftriaxone per susceptibilities. Due to persistent fevers, leukocytosis, and undiminished size of the hyperdensity on subsequent imaging, surgical intervention was pursued. Video-assisted thoracoscopic surgery revealed a left oblique fissure filled with purulence. Following successful thoracic decortication, the patient completed 5 weeks of ceftriaxone with symptom resolution. A follow-up CT of his thorax 8 months later.

Salmonella species are facultative aerobic Gram-negative rods, classified into typhoid and nontyphoid subtypes. While most commonly presenting as self-limited gastroenteritis, nontyphoid Salmonella (NTS) infection can rarely cause bacteremia and extraintestinal focal infections (EFIs), with mortality ranging from 30% to 40%. Endarteritis, septic arthritis, osteomyelitis, and pleuropulmonary infections are the most frequently identified EFIs, with the principal risk factor being an immunocompromised state. Long-standing, uncontrolled diabetes has been reported as a predisposing factor for EFIs through reduced gastric acidity and impaired gut motility from enteric neuropathy.

The multiloculated nature of the patient's empyema with a segment abutting the oblique fissure raised clinical suspicion for a possible intrapulmonary abscess. While differentiating empyema from pulmonary abscesses can be challenging, certain clinical and radiographic features can help distinguish the two entities. A patient with a lung abscess typically presents acutely with fevers and a productive cough.

Conversely, a patient with an empyema may manifest fevers over a subacute to chronic timeframe and sometimes lack a cough. On CT imaging, lung abscesses typically appear circular while an empyema forms a lenticular shape. In addition, pleural enhancement contiguous with the borders of the collection, as seen in this case, favors empyema. Empyema often necessitates drainage or excision, whereas pulmonary abscesses will often resolve with parenteral antibiotics alone. Chest tube placement in pulmonary abscesses carry an additional risk of bronchopulmonary fistula formation.

In conclusion, pleuropulmonary infections are a rare, potentially deadly manifestation of NTS infection in patients with uncontrolled diabetes. Longer symptom duration, lenticular shape, and contiguity with the pleura on imaging can help distinguish empyema from pulmonary abscess. Depending on its location and the patient's clinical status, empyema may require surgical intervention in addition to drainage to achieve resolution.

Source: https://www.jgid.org/article.asp?issn=0974-777X;year=2020;volume=12;issue=4;spage=219;epage=220;aulast=Solanky
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